1. Field of the Invention
This invention pertains to a chemical fire extinguishing apparatus in which the chemical extinguishing agent is fluidized by an inert gas and is discharged as a fluidized stream. More particularly, the invention relates to a method and apparatus for rapidly agitating and dispersing the chemical extenguishing agent within a storage facility and then discharging the chemical extinguishing agent at a controlled rate by means of fluidizing stream of a relatively lower pressure gas.
2. Brief Discription of the Prior Art
In dry chemical fire extinguishing systems, the concept of providing a storage location for a dry chemical fire extinguishing agent and connecting such storage location to a source of a gaseous fluidizing agent under pressure is well known. Thus, in U.S. Pat. Nos. 3,463,235 and 3,463,236, a cartridge of carbon dioxide is connected to the chemical storage drum or chamber. In order to deliver the extinguishing agent, the cartridges are punctured, and the pressurized carbon dioxide gas is admitted to the storage chamber to pick up and entrain the dry chemical extinguishing agent. In a different arrangment, a frangible disc employed to contain the gas under pressure is cut by a plunger in the manner shown in U.S. Pat. No. 2,778,434, or a frangible strip holding a removable ring pin is severed as shown in U.S. Pat. No. 3,061,194 for the purpose of releasing carbon dioxide. A cam-plunger arrangement has been proposed in U.S. Pat. No. 3,088,522 for the purpose of actuating the fire extinguishing system, utilizing pressurized gas. It has been proposed also to agitate and disperse the dry chemical fire extinguishing agent by inverting a drum or vessel which contains the agent at the time when it is to be entrained in a gaseous stream and delivered through distributing conduits. This concept is set forth in U.S. Pat. Nos. 2,923,360; 3,040,816; and 3,375,875.
In systems of the type described, the actuation of the fire extinguishing system is dependent upon the use of a stored pressurized gas which is released at the time of need to agitate and disperse the extinguishing agent within a storage facility, and also to entrain that agent in a moving gas stream directed to the fire. In other systems, the described agitation and dispersement to allow the agent to be picked up and carried in the gas stream is accomplished by inversion or mechanical movement of the storage container. In the type of actuation initially referred to, difficulties are sometimes encountered because of the inability of the pressurized gas to adequately disperse the dry chemical extinguishing agent which has become compacted or settled within the storage container. The pressure of the gas employed for this purpose and then subsequently for entrainment of the extinguishing agent does not afford sufficient shock and disturbance forces to break up and thoroughly disperse and agitate the chemical to allow adequate entrainment.
Where mechanicl movement of the drum or chamber is relied upon for agitating and dispersing the chemical extinguishing agent sotred therein, there must be provided relatively complicated mechanical systems involving heavy trunions, and frequently various types of hydraulic equipment, to effect the inversion of the chamber or otherwise move it in a way to agitate the stored chemical.